/*
练习1：使用fp.add(x, y)和fp.map(f, x)创建一个能
	让functor里的值增加的函数ex1
*/
const fp = require('lodash/fp')
const { Maybe, Container} = require('./support')
let maybe = Maybe.of([5, 6, 1])
let ex1 = () => {
	maybe.map(x=>{fp.map(fp.add(2), x)})
}
// console.log(ex1())
/*
练习2：实现一个函数ex2,能够使用fp.first获取列表的第一个元素
*/
let xs = Container.of(['do', 'ray', 'me', 'fa', 'so', 'la', 'ti', 'do'])
let ex2 = () => {
	return xs.map(x => fp.first(x))._value
}
// console.log(ex2())
/*
练习3：实现一个函数ex3,使用safeProp和fp.first找到
user的名字的首字母
*/
let safeProp = fp.curry(function(x, o) {
	return Maybe.of(o[x])
})
let user = {id: 2, name: 'Albert'}
let ex3 = () => {
	safeProp('name', user).map(x => x+'1')
	.map(x => fp.first(x))._value
}
// console.log(ex3())
/*
练习4： 使用Maybe重写ex4,不要有if语句
*/
/*let ex4 = function (n){
	if(n){
		return parseInt(n)
	}
}*/
let ex4 = Maybe.of(n)
